Function drop_on_clip

fn drop_on_clip<'a>(
    state: &TimelineState,
    p: &'a Project,
    pos: Pos2,
    t: f64,
) -> Option<(Rect, &'a Clip)>

The clip under a drop at screen pos / timeline time t, with its lane rect — what an effect or a transition dragged out of its panel is aimed at (app.rs resolves the same clip from the reported time + track when the drop actually happens).